Method for aligning a feeding beam in a rock drilling equipment and a rock drilling equipment and a measuring device

A method for aligning a feeding beam attached to the end of a boom turnable with respect to a carrier of rock drilling equipment, the feeding beam being turnable with respect to the boom when drilling holes in rock surfaces of the earth substantially in line and in the same plane comprising the steps of:

• determining a first angle between a longitudinal direction S.sub.a of the rock drilling equipment and a drilling direction S.sub.p ;
• aligning the feeding beam with the drilling direction S.sub.p in parallel with said plane by turning the boom with respect to the carrier and the feeding beam with respect to the end of the boom such that turning angles of said feeding beam with respect to said boom are determined on the basis of a second angle between the boom and the longitudinal direction S.sub.a of the carrier and the first angle between the longitudinal direction S.sub.a of said carrier and the drilling direction S.sub.p ;
• determining a reference direction S.sub.t independent of a magnetic field for each drilling position of the carrier;
• determining a third angle between the reference direction S.sub.t and the drilling direction S.sub.p ;
• determining the drilling direction S.sub.p at least after the first drilling position of the drilling equipment on the basis of the reference direction S.sub.t and the third angle;
• determining the first angle between the longitudinal direction S.sub.a of said carrier and the drilling direction S.sub.p on the basis of the determined drilling direction S.sub.p ;
• and
• aligning the feeding beam on the basis of the determined first angle so that it is parallel with the drilling direction S.sub.p and the drilling plane.